Inflammation is signaled by redness, swelling, heat, and pain as a reaction of the body against injury or assault. A variety of chemicals have been implicated as chemical mediators of the inflammatory reaction, including histamine, serotonin, kinins, prostaglandins, platelet-activating factors, leukotrienes, and, from nerve endings, substance P. Mediators of the acute inflammatory reaction seem to play roles in one or more of increasing vascular permeability, attracting leukocytes, producing pain, local edema, and necrosis.
A variety of physiologic responses occur from the biological events that constitute the inflammatory processes. For example, Pinckard et al. at Chapter 10 describe platelet-activating factors ("PAF") in the text Inflammation: Basic Principles and Clinical Correlates (Gallin et al. Ed., 1988). This family of structurally related compounds appear to promote a variety of physiologic actions that are directly or indirectly related to inflammatory reactions. The authors note that PAF has been implicated in the pathogenesis of human disease conditions such as endotoxin shock and organ transplantation rejection.
There are steroid and non-steroid, anti-inflammatory drugs known to the art. U.S. Pat. No. 4,579,844, inventors Rovee et al., issued Apr. 1, 1986, discloses topically treating an inflammatory condition of the skin by use of the prostaglandin synthetase inhibitor concurrently with a corticosteroid. U.S. Pat. No. 4,404,198, inventor Kelley, issued Sep. 13, 1983, discloses the topical application of a composition including phenyl salicylate to treat inflammation. U.S. Pat. No. 3,980,778, inventors Ayer et al., issued Sep. 14, 1976, discloses asteroid for use in the topical, oral or parenteral treatment of skin and mucous membrane inflammations. Ibuprofen (a known anti-inflammatory agent) has been tested in connection with UV-B-induced inflammation, but was found to have limited usefulness in treating sunburn reaction and is only somewhat more effective than placebo for the relief of symptoms associated with UV-B-induced inflammation after high dose UV-B phototherapy for psoriasis. Stern et al., Arch. Derm., 121, pp. 508-512 (1985).
U.S. Pat. No. 4,801,612, inventor Wei, issued Jan. 31, 1989, discloses the use of inhibiting an inflammatory response in the skin or mucosal membranes of a patient by administering corticotropin-releasing factor, or its analogs.
However, the microcirculation for mammals has its own selective pharmacology for each particular vascular bed. This means that an anti-inflammatory agent useful in one vascular bed, such as the skin and mucosal membranes, cannot predictably be useful with other vascular beds, such as the brain or musculature. For example, histamine, bradykinin, serotonin, or arachidonic acid failed to increase permeability in blood vessels of the pia mater (the innermost vascularized covering of the brain), although these substances are potent edema producing agents in the skin and mucosa. Another example of selective pharmacology is epinephrine, since this endogenous substance constricts blood vessels in the skin but dilates blood vessels in skeletal muscle. Thus, the permeability characteristics of the blood vessels (particularly the post-capillary venules) in a vascular bed such as the brain are not equivalent to those in the skin and mucosa.
Corticotropin-releasing factor (hereinafter "CRF") is a 41 amino acid neuropeptide that is present in brain and the peripheral nerve endings, and stimulates ACTH release from pituitary cells. U.S. Pat. No. 4,489,163, inventors Rivier et al., issued Dec. 18, 1984, discloses rat CRF and its analogs. Human CRF has the same sequence as rat CRF.
There are a number of analogs of CRF known to the art. U.S. Pat. No. 4,415,558, inventors Vale, Jr. et al., issued Nov. 15, 1983, discloses the synthesis of sheep CRF, analogs, and isolation of the oCRF from ovine hypothalamic extracts. The synthetic OCRF was found to lower blood pressure.
A generally similar peptide, sauvagine, was described in Regulatory Peptides 2, 1-13 (1981). Sauvagine is a 40 amino acid peptide and has been reported to have biological activity in lowering blood pressure in mammals and stimulating the secretion of ACTH and .beta.-endorphin.
U.S. Pat. No. 4,528,189, inventors Lederis et al., issued Jul. 9, 1985, and U.S. Pat. No. 4,533,654, inventors Lederis et al., issued Aug. 6, 1985, disclose peptides similar to the rat and sheep CRF and analogs thereof, and found this white sucker and carp urotensin respectively to stimulate ACTH and to lower blood pressure.
The other CRF-related peptide, white sucker urotensin, has an amino acid sequence the same as the carp urotensin, except the amino acid at the 24 position is isoleucine and the amino acid at the 27 position is glutamic acid.
Ling et al., BBRC, 122, pp. 1218-1224 (1984), disclose the structure of goat CRF, which is the same as that for sheep CRF. Esch et al., BBRC, 122, pp. 899-905 (1984), disclose the structure of bovine CRF which differs from sheep and goat CRF only by one amino acid residue (number 33 which is Asparagine rather than the number 33 Serine of goat and sheep CRF). Porcine CRF has been isolated and characterized by Patthy et al., Proc. Natl. Acad. Sci., 82, pp. 8762-8766 (1985). Porcine CRF shares a common amino acid sequence (residues 1-39) with rat/human CRF and differs from these only in position 40 and 41. Residue 40 can be either asparagine or isoleucine and residue 41 is phenylalanine-amide.